One of the known methods for texturing or texturizing a synthetic yarn is known as the "knit/deknit" process in which a yarn end is tightly knit into a tubular prefabric, the stitch is heat set, and the prefabric is then unraveled (deknit) and taken up onto a yarn carrier. Treated in this manner the resulting yarn has a characteristic texture and bulk, or "crinkle". One of the side advantages of the knit/deknit process is that while the yarn is in the tubular prefabric form it can be space dyed, so that upon deknitting, there is formed a yarn of multicolors.
The most common practice in space dyeing the tubular prefabric is to pass the tube lengthwise through a printing operation wherein the colors are printed thereon as described in U.S. Pat. No. 3,012,303, issued Dec. 12, 1961. A somewhat different approach is taken in U.S. Pat. No. 3,828,405 issued Aug. 13, 1974 in which the tubular prefabric is again advanced lengthwise along a predetermined path while dyestuff is freely dribbled thereon from a nozzle overlying the path of travel, whereupon the tube is passed through rolls which press the tube flat and force migration of the dyestuff differentially throughout the material.
In each of the aforementioned methods, it is necessary to advance the tubular fabric lengthwise past a dye station or through printing rolls. The knit tube, upon completion of the knitting operation, is conventionally rolled upon itself or a carrier into a coil-type package comprising a plurality of convolute layers of knit tubing. During the dyeing operations according to the above-mentioned processes, the knit tubing must be completely unrolled and processed linearly or lengthwise past the dyeing station.
A roll or package of tubing contains about 500-700 linear feet of knit tubing. When the knit tubes must be unrolled and passed lengthwise by the dye station, the dyeing operation takes at least 20-30 minutes per package, depending upon the length, consistency of the dyestuff, and the like. Further, according to general practices, the knit tubing is subjected to an autoclave to set the stitch after the knitting operation, then the dyed tube is passed through a dry oven prior to rolling or coiling to set the color therein. Obviously such dyed rolls cannot be autoclaved prior to or simultaneously with heat setting, since the colors would run onto the adjacent layers.
The time consuming processes described hereinabove have caused prices for yarn dyed in this manner to remain so high that the use of such yarn has been severely restricted.